This 2-year longitudinal study will investigate the relation of early medical complications associated with prematurity on the development of low birth weight (LBW) infants. The ability of caretaking factors to facilitate or impede development in these infants will be evaluated. We will also investigate the relation of a group of maternal social and personal predictors to changes across time in the quality of mothers' caretaking skills. The study will focus on the lower socioeconomic environment in which the increased likelihood of premature birth, combined with the developmental risks associated with social and parenting factors, place the infant at double jeopardy for poor outcome. A group of 240 low SES LBW infants and 120 full-term infants matched for SES and maternal age will be followed from birth to 2 yr. LBW infants will be recruited for 2 risk groups of equal size according to the etiology and severity of their early medical complications. These complications are all associated with central nervous system damage, which appears to result primarily from either focal brain lesion (e.g., intraventricular hemorrhage, periventricular leucomalacia) or from recurrent episodes of hypoxia secondary to respiratory disorders (e.g., respiratory distress syndrome, bronchopulmonary dysplasia). Specific medical complications will be indexed and their relation to infant development will be separately evaluated. The inclusion of a normal, full-term group will allow us to assess the degree to which infants with low or high risk medical complications differ in rates of development from infants with normal perinatal histories. The development of a broad range of skills and behaviors will be assessed at 6, 12, and 24 mos of age in conjunction with measures of caretaking factors and predictors of parenting. The increasing survival rate for the LBW preterm infant In technologically sophisticated neonatal intensive care facilities has created a critical need for accurate predictors of developmental outcome. Determining which environmental factors impede and which buffer parents' attempts to care for preterm infants, especially in the low SES home, will facilitate development of appropriate interventions to improve the quality of life and social productivity of infants most at risk for developmental delay and potentially permanent disability.